Arrangement for the identification of potential differences



1951 R. M M. OBERMAN ETAL 2,577,147

ARRANGEMENT FOR THE IDENTIFICATION OF POTENTIAL DIFFERENCES Filed Aug. 20, 1949 2 'SHEETSSHEET l 2 2 wbw- 4 61""\T I LV1 i fg -T 1 o \+1 +2 0 POTENTIAL DIAGRAM Dec. 4, 1951 R. M. M. OBERMAN ETAL 2,577,147

ARRANGEMENT FOR THE IDENTIFICATION OF POTENTIAL DIFFERENCES ANODE CURRENT GRAPH Patented Dec. 4, 1951 ARRANGEMENT FORTHE' IDENTIFICATION OF POTENTIAL DIFFERENCES Roelof M. M. Oberman and Antoniesnijders, The Hague, Netherlands Application August'20; 1949, Serial'No. 111,394 In the Netherlands March 23,1946

Claims.

The present invention relates to an arrangement'for the identification of potential differences by meansof two electron tubes, the potential difference to be identified being applied between the control grid and the cathode of each tube.

An arrangement of this kind for A. C. voltages is described in the U. S. Patent No. 1,574,808, where for the identification of the amplitude of an A. C. voltage two electron tubes are used which are connected to the relevant input terminals by the application of variouspreceding voltages.

It is, an object. of the present invention to provide an arrangement ofthistype which iSsIiitable :to be operated with direct current.

v.It is another object ofthe present invention to providean arrangement for the identification of potential differences which is reliable in operation and can be easily adjusted to different ranges of operation.

The arrangementaccording to the-present invention'comprises in combinationa first electron tube having a cathode, a grid and an anode, means for applying the potential difference to be identified between the cathode and the grid of the first electron tube, a second electron tube having a cathode, a grid and an anode,'means for applying the potential difference to be identified between the cathode and the grid of the second electron tube, means for shifting the control voltage anodecurrent characteristic of the second tube with respect to that of the' first tube, a potentiometer having one of itsends connected to the anode of the first tube, a phase reversing tube including acathode, a grid and an anode, a tap-in the potentiometer connected to the grid of the phase reversing tube, the anode of the phase, reversing tube. being interconnected to the anode of the second tube, and a device connected to .theanode of the phase reversing tubeior passingacurrent when the voltage of the interconnectionof the anodes of the phase reversing tubeandthesecondtube is between two predetermined values.

.Ina preferred embodiment of the invention, anend tube isprovided having-a cathode, a grid andan anode, a second potentiometer having one of its ends connected to the anodeof the phase reversing tube, and a tap in thesecond potentiometer connected to the grid-of the end tube.

The, operational range of the arrangement can be adjusted, iicdesiredby a suitable choice of D. ,C'. voltage sources inserted in the lead from one .of the input terminals.

The novel features which'we consider as characteristic for our invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method or operation, together with additional objects'and advantages thereof will be best understoodffrom thefollowing description of specific embodiments 'wlien read in connection with the accompanying'drawings, in which:

Fig. 1 is a circuitdiagram of an arrangement according to the invention;

Fig.2 shows the anode current characteristics of the four tubes shown: in Fig. 1 as function of the input voltage'of the" arrangement; and

"Fig. ii-shows the voltages'of'some characteristic'points'of the'arrangement shown in Fig.1, also -as functions of the input voltage of the arrangement.

Referring now to Figure 1, the input terminals 1 and 2 are shown to which the potential differencesto' be identified are applied which are, for instance, derived from the same direct voltage source. "These voltages are chosen, for instance, as multiples of 2 volts. A certain potential can be applied to the terminal 2, while the other terminal I is connectedto the test Wiper of a switch, for instance, in telephone systems, which is moved on over a row of contacts until the identification device according to Figure 1 determines that a. contact has been reached with a potential which is almost equal to the one which is applied to terminal 2. The identification device comprisesfour high vacuum tubes Bl to B4, which are coupled by means of resistances. The resistances WI,'W2, W6. and Will are protecting resistances for the tubes against positive input voltages. The anode of the tube BI is connected over the resistance W3 to the anode voltage source VI and over a potentiometer consisting of the resistances W4 and W5 to the negative pole of'an auxiliary voltage source V2, which has approximately the same voltage as the anode voltage source VI. The tap point bl is connected over a resistance WI I to the cathode circuit.

The anode current of the tube Bl as a function of the input voltages is shown in Figure 2. The tube has a grid voltage space of about 2 volts. The anode voltage of this tube is shown in Figure 3 as .function of the input voltage (curve al). The voltage of the point bl can be adjusted bya suitable choice of theresistances W4, W5, and WI I, so that the tube B3 acts only as phase reversing tube Without amplification. The point bl is connected over the protecting resistance W6 to'thecontrol grid of the tube B3.

As it appears from the anode current charac teristic of the tube B3 shown in Figure 2, the tube is in conductive position for high negative input voltages, while it becomes non-conductive between -2 volts and volt input voltage in contradistinction to tube BI.

The anode voltage characteristic of the tube B3 is shown in Figure 3 by the curve (1%.

The tube B2 is arranged in a manner analogous to that of the tube Bl. The anode current characteristic of thi tube is shifted by means of the voltage source V4 so that in the diagram it is 2 volts to the right with respect to that of the tube Bl. Therefore, the tube B2 becomes conductive at input voltages between 0 and +2 volts. The downward sloping part of the anode voltage characteristic of the tube B2 in Figure 3 (curve 11%) is also 2 volts to the right of that of the tube Bl (curve al).

The anodes of the tubes B2 and B3 are interconnected so that the collective anode voltage characteristic of these tubes, represented by the curve (1 in Figure 3, represents the voltage at the point 11%.

From the potentiometer comprising the resistances W8 and W9, which is arranged between the point a and the negative pole of the auxiliary voltage source V2, the control voltage at the grid of the end tube B4 is derived, which is represented in Figure 3 by the curve b2.

The anode current characteristic of the end tube B4 is shown in Figure 2. The end tube is non-conductive from a high negative input voltage to -1 volt, then becomes rapidly conductive and remains so almost constantly unto an input voltage of +1 volt, where the tube rapidly returns to the non-conductive condition to remain nonconductive up to the highest admissible positive input voltage.

A relay R, inserted in the anode circuit of the end tube B4, attracts its armature when a potential difference between -1 volt and +1 volt is applied to the input terminals. A contact of the relay R can interrupt the movement of the above mentioned switch.

The operational range of the arrangement can be adjusted by D. C. voltage sources V3 and V4 inserted in the lead from the terminal 2 and the lead connecting the same to the cathode of tube B2. If desired, the voltage sources V3 and V4 can also be derived automatically from the arrangement by means of resistances.

The phase reversing tube can also operate as 4 an amplifying tube when the resistance Wll is omitted and the resistance W4 and W5 are differently dimensioned. In consequence of this, the end tube B4 becomes conductive under the control of the tube Bl almost in jumps or jerks, which may be necessary or desirable for certain applications of the arrangement.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of arrangements for the identification of potential differences, differing from the types described above.

While we have illustrated and described the invention as embodied in arrangements for the identification of potential difierences, we do not intend to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the,

it for various applications without omitting fea-' tures that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention, and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What we claim as new and desire to secure by Letters Patent is:

1. An arrangement for the identification of potential differences comprising in combination a first electron tube having a cathode, a grid and an anode; means for applying the potential differenceto be identified between said cathode and said grid of said first electron tube; a second electron tube having a cathode, a grid and an'anode; means for applying the potential difference to be identified between said cathode and said grid of said second electron tube; means for shifting the control voltage anode current characteristic of said second tube with respect to that of said first tube; a first potentiometer having one of its ends connected to said anode of said first tube; a phase reversing tube including a cathode, a grid and an anode; a tap in said first potentiometer connected to said grid of said phase reversing tube; said anode of said phase reversing tube being interconnected to said anode of said second tube; an end tube having a cathode, a grid and an anode; a second potentiometer having one of its ends connected to said anode of said phase reversing tube; and a tap in said second potentiometer connected to said grid of said end tube.

2. An arrangement for the identification of potential differences comprising in combination a first electron tube having a cathode, a grid and an anode; means for applying the potential difference to be identified between said cathode and said grid of said first electron tube; a second electron tube having a cathode, a grid and an anode; means for applying the potential difierence to be identified between said cathode and said grid of said second electron tube; a direct voltage source for shifting the control voltage anode current characteristic of said second tube with respect to that of said first tube; a first potentiometer having one of its ends connected to said anode of said first tube; a phase reversing tube including a cathode, a grid and an anode; a tap in said first potentiometer connected to said grid of said phase reversing tube; said anode of said phase reversing tube being interconnected to said anode of said second tube; an end tube having a cathode, a grid and an anode; a second potentiometer having one of its ends connected to said anode of said phase reversing tube; and a tap in said second potentiometer connected to said grid of said end tube.

3. An arrangement for the identification of potential differences comprising in combination a first electron tube having a cathode, a grid and an anode; means for applying the potential differenoe to be identified between said cathode and said grid of said second electron tube; means for shifting the control voltage anode current characteristic of said second tube with respect to that of said first tube; a first potentiometer having one of its ends connected to said anode of said first tube; an auxiliary direct voltage source having a terminal connected to the other end of said first potentiometer; a phase reversing tube including a cathode, a grid and an anode; a

tap inrsaid first potentiometer connected to 'said grid of said phase'reversing tube; said anode of saidphase reversing tube being interconnected .tofsaid anode of said second tube; an end tube having "a cathode, a grid and an anode; a second'potentiom'eter having one of its ends con nected to said anode of said phase reversing tube;'and.a tap in said second'potentiometer connected to said grid of saidend tube.

a. An arrangement for the identification of potential differences comprising in combination a first electron tube having a cathode, a grid and an anode; means for'applying the potential diiierence to be identified between said cathode and said grid of said first electron tube; a second electron tube having a 'cathode, ia-grid and an anode; means for applying'the potential difference I to be identified between said cathode and said grid of said second electron tube; means for shifting the control voltage anode current characteristic of said second tube with respect to that of said first-tube; a first potentiometer having one of its endsconnected to said'anode of said first tube; an auxiliary direct voltage source having a negative terminal connected to the other end of said first potentiometer; an anode voltage source having a negative terminal connected to the positive terminal of said auxiliary direct voltage source; a phase reversing tube including a cathode, a grid and an anode; a tap in saidfirst potentiometer connected to said grid of said phase reversing tube; said anode of said phase reversingtube being interconnected to said anode of said -second'tube; and 'an end tube having a cathode, a grid and an :anode; a second potentiometerhavingione of its ends connected to said anode of said phase reversing tube; and a tap in said second potentiometer connected to said grid of said end tube.

5. An arrangement for the identification of potential differences comprising in combination a first electron tube having a cathode, a grid and an anode; means for-applying the potential difference to be identified between said cathode and said grid of said first electron tube; a second'electron tube having a cathode, a grid and an anode; means for applying the potential difference to be identified between said cathode and said grid of said second electron tube; a direct voltage source for shifting the control voltage anode current characteristic of said second tube with respect to that of said first tube; a first po tentiometer having one of its ends connected to said anode of said first tube; an auxiliary direct voltage source having a terminal connected to the other end of said first potentiometer; a phase reversing tube including a cathode, a grid and an anode; a tap in said first potentiometer connected to said grid of said phase reversing tube; said anode of said phase reversing tube being interconnected to said anode of said second tube; an end tube having a cathode, a grid and an anode; a second potentiometer having one of its ends connected to said anode of said phase reversing tubes; and a tap in said second potentiometer connected to said grid of said end tube.

6. An arrangement for the identification of potential difierences comprising in combination a first electron tube having a cathode, a grid and an anode; means for applying the potential dif ference to be identified between said cathode and said grid of said first electron tube; a second electron tube having a cathode, a grid and an anode; means for applying the potential difierence to be identified between said cathode and said grid of an anode;

said secondele'ctrontube'; a direct voltage source for shifting the control voltage anode current charac'teristicof 'said second tube with-respect to that of said first tube; a'first potentiometer having one of its ends connected to said anode of said :first itube; an auxiliary direct voltage source having a negative terminal connected to the other :end of said first potentiometer; an anode voltage source having a negative terminal con nected to the positive terminal oi'saidsauxiliary direct voltage source; a phase reversing tube including a cathode, a grid and an anode; a tap in said first potentiometer connected to said grid of said phase reversing tube; said anode of said phasereversing tube being interconnected to said anodeof'said second tube; an end tube having a cathode, a grid :andan anode; a second potentiometer having one of its ends connected to said anode of said'phase reversing tube; and a tap in saidsecond potentiometer connected to said-grid of said end tube.

'7. An arrangement for the identification of potential differences comprising in combination a firstielectron tube having a, cahode, a grid and an anode; means for applying the potential dif ference -to be identified between said cathode and said grid of said first electron tube; a second electron tube having a cathode, a grid and an anode; means for applying the potential difference to be identified between said cathode and said grid of said secondelectron tube; means for shifting the control voltage anode current characteristic of said'second tube with respect to that of said first tube; a first potentiometer "having one ofits ends connected to said anode of said first tube an1auxilia1y direct voltage source'having a negative terminal connected to the other end of'said first potentiometer; an anode voltage source'having a negative terminal connected to the positive terminal of said auxiliary direct voltage source; a phase reversing tube including a cathode a-grid and an anode; a tap in said first potentiometer connected to said'grid of said phase reversing tube; said anode of said phase reversing tube being interconnected to said anode of saidisecond tube; an end tube having a cathode, a grid and an anode; a second poteniometer having one of its ends connected to said anode of said phase reversing tube, the other end of said second potentiometer being connected to the negative terminal of said auxiliary direct voltage source; and a tap in said second potentiometer connected to said grid of said end tube.

8. An arrangement for the identification of potential differences comprising in combination a first electron tube having a cathode, a grid and an anode; means for applying the potential difference to be identified between said cathode and said grid of said first electron tube; a second electron tube having a cathode, a grid and an anode; means for applying the potential difference to be identified between said cathode and said grid of said second electron tube; a direct voltage source for shifting the control voltage anode current characteristic of said second tube with respect to that of said first tube; a first potentiometer having one of its ends connected to said anode of said first tube; an auxiliary direct voltage source having a negative terminal connected to the other end of said first potentiometer; an anode voltage source having a negative terminal connected to the posilive terminal of said auxiliary direct voltage source; a phase reversing tube including a cathode, a grid and a tap in said first potentiometer con- 7 nected to said grid of said phase reversing tube; said anode of said phase reversing tube being interconnected to said anode of saidsecond tube;

an end tube having a cathode, a grid and an anode; a second potentiometer having one of its ends connected to said anode of said phase reversing tube, the other end of said second potentiometer being connected to the negative terminal of said auxiliary direct voltage source; and a tap in said second potentiometer connected to said grid of said end tube.

9. An arrangement for the identification of potential difierences comprising in combination a first electron tube having a cathode, a grid and an anode; means for applying the potential difference to be identified between said cathode and said grid of said first electron tube; said means including a direct voltage source connected in series to said cathode of said first electron tube; a second electron tube having a cathode, a grid and an anode; means including a direct voltage source connected in series to said cathode of said second electron tube for applying the potential difference to be identified between said cathode and said grid of said second electron tube; means for shifting the control voltage anode current characteristic of said second tube with respect to that of said first tube; a first potentiometer having one of its ends connected to said anode of said first tube; an auxiliary direct voltage source having a negative terminal connected to the other end of said first potentiometer; an anode voltagesource having a negative terminal connected to the positive terminal of said auxiliary direct voltage source; a phase reversing tube including a cathode, a grid and an anode; a tap in said first potentiometer connected to said grid of said phase reversing tube; said anode of said phase reversing tube being interconnected to said anode of said second tube; an end tube having a cathode, a grid and an anode; a second potentiometer having one of its ends connected to said anode of said phase reversing tube; and a tap in said second potentiometer connected to said grid of said end tube. V

10. An arrangement for the identification of potential difierences comprising in combination a first electron tube having a cathode, a grid and an anode; means for applying the potential difference to be identified between said cathode and said grid of said first electron tube, said means including a direct voltage source connected in series to said cathode of said first electron tube; a second electron tube having a cathode, a grid and an anode; means including a direct voltage source connected in series to said cathode of said second electron tube for applying the potential difierence to be identified between said cathode and said grid of said second electron tube; a direct voltage source for shifting the control voltage anode current characteristic of said second tube with respect to that of said first tube; a first potentiometer having one .of its ends connected to said anode of said first tube; an auxiliary direct voltage source having a negative terminal connected to the other end of said first potentiometer; an anode voltage source having a negative terminal connected to the positive terminal of said auxiliary direct voltage source; a phase reversing tube including a cathode, a grid and an anode; a tap in said first potentiometer connected to said grid of said phase reversing tube; said anode of said phase reversing tube being interconnected to said anode of said second tube; an end tube having a cathode, a grid and an anode; a second potentiometer having one of its ends connected to said anode of said phase reversing tube, the other end of said second potentiometer being connected to the negative terminal of said auxiliary direct voltage source; and a tap in said second potentiometer connected to said grid of said end tube.

ROELOF M. M. OBERMAN. ANTONIE SNIJDERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,252,599 Lewis Aug. 12, 1941 2,434,922 Grieg Jan. 2'7, 1943 

